Ceramic grinding machine tool

Some research departments at home and abroad have successively developed grinding machines suitable for ceramic material processing, mainly making appropriate improvements to existing metal grinding machines. Mainly including machine tool structure, grinding wheel dressing system, cooling device, sealing and protection system, clamping accessories, etc. Generally, grinding machines for ceramic material processing should meet the following functional requirements:

(1) The structural stiffness of the grinding machine should be high. The stiffness of the machine bed and grinding wheel spindle should be high, and the static stiffness of the spindle is generally 3-5 times that of a regular grinding machine.

(2) The power of the grinding wheel spindle drive motor should be high.

(3) The machine tool is equipped with dust prevention facilities, especially for moving parts such as guide rails and screws, attention should be paid to protection.

(4) A eaves ring system with working fluid supply, filtration, and separation of grinding debris.

(5) The grinding machine uses diamond grinding wheels as grinding tools and is equipped with corresponding diamond grinding wheel dressing devices.

The stiffness of ceramic grinding machines has always been a focus of attention. The main factors causing structural deformation of machine tools include thermal deformation, static load, dynamic load, and residual stress. Among them, thermal deformation is the main factor causing machine tool deformation, as the thermal deformation of the machine tool structure will cause changes in the position of the workpiece relative to the grinding wheel. To reduce the impact of temperature field on machine tool structure, various measures can be taken, including active and passive measures

Static load is another factor that causes structural deformation of machine tools. During ceramic grinding, the ratio of normal force to tangential force can reach 10:1, and higher normal force can easily cause spindle deformation. Therefore, the design of static stiffness for ceramic grinding machines is very important. The static stiffness of the machine tool structure depends on the structural material and component design. Static load not only affects machining accuracy, but also is related to the productivity of the machine tool.

The dynamic characteristics of machine tools also affect the machining process of ceramic materials. Grinding vibration is often caused by insufficient closed-loop stiffness of machine tools (usually referring to the stiffness between the grinding wheel and the workpiece) and grinding wheel wear. In addition, the increase in machine tool stiffness also leads to a decrease in the strength of the processed workpiece, which is mainly affected by the dynamic grinding force component in the grinding force.

In order to improve the stability of the machine tool, materials with good dimensional stability can be used to manufacture the machine tool bed, such as granite, alloy cast iron, etc. In addition, some components undergo stress relief process to ensure that these components have high dimensional stability.

Ceramic debris is in the form of fine powder and is a hard point with high hardness. If entering the bearings, guide rails, and other mating surfaces of the machine tool, it will exacerbate the wear of the machine tool. Therefore, the design of protective and cooling cleaning devices for key components is one of the key technologies in the design process of ceramic grinding machines. The electromagnetic coolant eyebrow removal method is not suitable for ceramic debris. In ceramic processing, methods such as flotation, alluvial filtration, and centrifugal filtration are usually used to clean the coolant.

Table 2 lists several clamping methods for ceramic materials. During the clamping process of ceramic workpieces, it is necessary to ensure that the clamping force of the workpiece is uniform and consistent, to avoid the occurrence of stress mutation points, which may cause damage to the workpiece due to clamping. Especially for thin-walled workpieces, it is necessary to design specialized fixtures to ensure the grinding process of the workpiece. Because ceramic workpieces do not conduct electricity, they cannot be directly applied to electromagnetic suction cup worktables and require the use of a vise to hold the workpiece. For batch grinding of flat parts, it is necessary to design specialized fixtures to improve processing efficiency.

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